Heat the olive oil in a large dutch oven over medium-high heat. Season the chicken lightly with kosher salt and cracked black pepper.
Sear each side for 2-3 minutes, or until it is no longer pink. Remove the chicken to a plate and set it aside.
Add the butter, carrots, celery, and onion. Cook for 3-5 minutes, or until the vegetables are just beginning to soften.
Next add the garlic and thyme. Cook for an additional minute. Sprinkle over the flour and stir to coat the vegetables in flour.